UASt regulatory sequences drive expression of a constitutively active form of Cdc42 (carries amino acid substitutions Q79L, E91H and N92H) that is tagged at the N-terminal end with mCherry. The Cdc42 sequence is also tagged with a mutated Phototropin LOV2 domain (carries the C450M mutation that stabilizes the dark-state conformation), and acts as a light-insensitive control.